Kinematics of Stellar Systems: Distances, Mass Distributions, and Binary Star Frequencies

“恒星系统的运动学：距离、质量分布和双星频率”这个项目研究我们银河系的矮球状伴星系的结构、恒星含量和球状星团的动态演化以及暗物质含量。利用罗格斯法布里-佩罗成像仪可以获得的大量数据。该仪器是少数能够获得解决这些挑战所需的宽视场径向速度数据的仪器之一。结合法布里-佩罗测量的径向速度分布和HST对成员恒星固有运动分布的测定，将产生13个球状星团距离的直接几何测量。这些新距离的不确定性约为目前接受值的五分之一。重复的速度测量是发现双星最有效的方法之一，而预期的大量增加的速度测量将测试球状星团双星动态演化的模型。该项目将使用三色恒星测光技术和宽视场成像仪来搜索与天龙座矮球状星系相关的恒星碎片的潮汐尾。通过测量恒星的径向速度，可以得出矮球状星系的总暗物质质量和恒星从星系中消失的速度。因此，在这个奖项下所做的工作将影响天体物理学的几个领域，包括河外距离尺度和矮球状星系中暗物质的特征。

"Kinematics of Stellar Systems: Distances, Mass Distributions and Binary Star Frequencies"AST-0098650This project investigates the structure, stellar content and dynamical evolution of globular clusters and of the dark matter content of the dwarf spheroidal companion galaxies of our own Milky Way. Advantage is taken of the enormous amount of data that can be obtained with the Rutgers Fabry-Perot imager. This instrument is one of the few that can acquire the wide-field radial velocity data which are required to address these challenges. Combining Fabry-Perot measurements of the radial velocity distribution with HST determinations of the distribution of proper motions for member stars will yield direct geometrically based measures of the distances to 13 globular clusters. These new distances will have uncertainties about one-fifth as large as the currently accepted values. Repeated velocity measurements are one of the most productive ways of discovering binary stars and the greatly increased numbers which are expected will test models for the dynamical evolution of globular cluster binaries. The project will use three-color stellar photometry with the wide-field imagers to search for tidal tails of stellar debris associated with the Draco dwarf spheroidal galaxy. Radial velocity measurements of the stars thus found can yield total dark matter masses for the dwarf spheroidal galaxy and the rate at which stars are being lost from the system. Thus, the work done under this award will impact upon several areas of astrophysics including the extragalactic distance scale and the characteristics of dark matter in dwarf spheroidal galaxies.